REST APIs

2025-04-13

REST APIs

Title: Understanding REST APIs: Methods, Status Codes, and How They Work

Introduction: What is an API?

An API (Application Programming Interface) is a way for two software systems to talk to each other. APIs allow developers to access functionalities or data from another application or service without knowing how it's built underneath.

For example, when you log in to a website using Google or Facebook, your browser is using their API to authenticate you.

What is a REST API?

REST stands for Representational State Transfer. A REST API follows a set of rules and conventions that make it easy to understand and use. It typically uses HTTP methods to perform actions on resources (like users, products, posts, etc.).

Key characteristics of REST APIs:

  • Stateless: Each request is independent.
  • Uses standard HTTP methods.
  • Data is usually sent and received in JSON format.
  • Resources are accessed via URLs.

HTTP Methods in REST API

Here are the most common HTTP methods used in REST APIs:

Method Description Example Endpoint
GET Read or fetch data /api/users
POST Create a new resource /api/users
PUT Update an existing resource /api/users/1
PATCH Partially update a resource /api/users/1
DELETE Delete a resource /api/users/1

HTTP Status Codes

APIs use status codes to indicate the result of a request. Here's a list of common ones:

✅ Successful Responses

Code Meaning Description
200 OK Request succeeded
201 Created Resource successfully created
204 No Content Request succeeded, no response body

❌ Client Errors

Code Meaning Description
400 Bad Request Invalid input or missing data
401 Unauthorized User not authenticated
403 Forbidden Authenticated but not allowed
404 Not Found Resource doesn't exist

🚨 Server Errors

Code Meaning Description
500 Internal Server Error Generic server error
503 Service Unavailable Server is temporarily offline

Example: Simple REST API for Users

Let’s say we have a REST API for managing users:

  • GET /api/users – Get all users
  • GET /api/users/1 – Get user with ID 1
  • POST /api/users – Create a new user
  • PUT /api/users/1 – Update user with ID 1
  • DELETE /api/users/1 – Delete user with ID 1

Conclusion

REST APIs are the backbone of modern web development. Understanding the basic methods and status codes makes it much easier to integrate APIs into your apps or even build your own.

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